I can't figure this out

[gwtank]

I'm new to the hobby and have had my fish only tank setup for about 8 months. I've been doing the required regular maintence and my tank has been running great, and still is for the most part. About two or three days ago I notcied small particles floating around the tank, I thought they may be air bubbles from a leak or something in my return hose so here are the steps that I took to isolate:
- lowered the return head about 3 inches from the waterline
- swapped the return hose with the suction hose
Since then I've changed some filter media and did a 50% water change.
none of that fixed it. I even turned off the canister filter for a night and the gunk is still floating around the tank. All the fish are doing fine and don't seem effected by it, but it makes the tank look dull and kinda cloudy. Any ideas?

 

[broomer5]

Any chance you may have some algae growing in your hoses ?
I used clear vinyl tubing for some of my returns, it's been about 8 months for my tank since set up, and these hoses have some crud growing inside the walls of the hose.
It may just be a thick bacterial slime coating that has built up in the hose, and is sluffing off some of it into the tank.
When I start up the return pump(s), some of this stuff comes out sometimes as very small particles.
Sorta whitish grey looking bits - floaters for sure, but very small.
Think it's time to replace them and use black hose from now on.
This is just a guess - but I'm experiencing something sorta similar.

 

[gwtank]

That might be what it is... they look exactly like what you are describing but the tubes to my canister are solid so I can't tell. I think I'll be going to the local fish store to get some clear tubing tomorrow and see if that clears it up.
Thanks for the response.